This invention relates to the production of vehicle tires and especially to the processing of tires following their removal from a vulcanizing mold. More particularly, the invention relates to the procedure for removing or trimming from the tire, mold vents, mold flash and the like.
The invention has particular utility in connection with the post-cure processing of larger tires such as truck tires and tires for off-the-road equipment. After such tires are cured in a vulcanizing mold, it is necessary to trim or remove undesired protruberances from the tread and sidewall portions. Such protruberances include material that squeezes into small vents in the mold during the vulcanizing operation and material or flash that squeezes into spaces at the parting lines between mold sections.
According to existing practices, the tire to be trimmed is manually loaded in an apparatus that spins the tire about its axis of rotation while an operator, using one or more drag knives, cuts or trims away the undesired material from the spinning tire. The trimmed tire is then manually removed from the trimming station by the operator.
Truck tires, off the road tires, and the like are quite heavy and difficult to handle manually. Accordingly, the trimming operation for such tires is burdensome and time consuming. Also, manufacturing facilities for such tires are adapted to produce as many as several hundred different types of tires varying greatly in dimension, type of construction (e.g. bias or radial carcass construction) and/or tread design. Nevertheless, it is usually necessary to trim a manufacturing facility's entire production at one trimming station.
One difficulty often encountered with this arrangement is that the surface speed at which a relatively large tire is spun for the trimming operation may be effective for tires of one size but for tires of other sizes the drag knives may catch the tread rubber and be jerked out of the operator's hand. In view of this problem, the general rule is that slower surface speeds be used with tires of larger diameter. Measuring the tire diameter and adjusting the spin speed, however, is a complicated problem and generally not practical with most conventional equipment.
The apparatus of the present invention, however, resolves many of the difficulties indicated above and affords other features and advantages heretofore not obtainable.